Juvenile dystonic lipidosis: an unusual form of neurovisceral storage disease

Sphingomyelin-induced structural modification of native human hemoglobin and its chemically and thermally disrupted secondary structure: A photophysical exploration

Sphingomyelin-induced structural modification of Human Hemoglobin (Hb) has been investigated in its native and unfolded conformers that are partially denatured in presence of ∼ 4 M urea, completely denatured in ∼ 8 M urea and thermally disrupted (at ∼ 65 °C) state. The absorption studies unveil ground state complexation between Hb and SM. From steady-state fluorescence and quenching studies alteration of the micro-environments around Trp residues of Hb in above mentioned different cases has been determined. Moreover, lesser exposure of Trp residues to SM in thermally disrupted Hb can be accounted for the exceptionally interesting outcomes in other experiments. The alterations in the time-resolved decay profiles of native Hb, partially and totally chemically denatured as well as thermally disrupted Hb with gradual addition of SM also affirm the amendment of the proteinous micro-environment surrounding Trp residues in a view of FRET between Trp residues and heme group. Wavelength-sensitive emission spectral studies reveal that the protein shows red edge effect in its different conformations in presence and absence of SM. Interestingly, the wavelength-responsive time-resolved study at a constant excitation wavelength demonstrates that with addition of lipid the increment of the average fluorescence lifetime signifies a considerable modulation of solvation dynamics of the fluorescent Trp residues in their excited state being greatest in case of thermally disrupted Hb. Nevertheless, the loss of α-helicity of Hb at its various conformers with addition of SM has been portrayed thoroughly by means of far-UV CD spectral studies in a view of disruption of secondary structure of the protein.

Niemann-Pick disease type C: two cases and an update

We describe two patients with juvenile-onset Niemann-Pick disease type C (NPC) to illustrate the variable neurologic features of this condition. One presented with hypersplenism at age 10 and was misdiagnosed with Gaucher disease. He developed complex partial seizures in his teens but remained otherwise neurologically asymptomatic until his mid 30s. At age 45, he had mild dementia and dysarthria, vertical supranuclear ophthalmoplegia, axonal sensorimotor polyneuropathy, and cerebellar ataxia. The second patient presented with rapidly progressive dystonia at age 8, and mild hepatosplenomegaly, vertical supranuclear ophthalmoplegia, severe behavioral disorder, and dementia by age 14. The diagnosis of NPC was based on deficient cholesterol esterification and excessive lysosomal filipin staining in cultured skin fibroblasts. Current notions about diagnosis and pathogenesis of NPC are reviewed.

Magnetic resonance spectroscopy in Niemann-Pick disease type C: correlation with diagnosis and clinical response to cholestyramine and lovastatin

Niemann-Pick type C is an autosomal-recessive, neurovisceral storage disorder that results from defective cholesterol esterification. Cholesterol-lowering agents have been demonstrated to decrease hepatic lipids in Niemann-Pick type C patients. The objective was to determine the effects of cholesterol-lowering agents on neurologic features and to develop a noninvasive method of monitoring clinical response. A 9-month-old boy with progressive hepatosplenomegaly and neurodevelopmental delay was studied. Water-suppressed proton magnetic resonance spectra from a supraventricular volume of central white and gray matter revealed an abnormal lipid signal. The patient was treated with cholesterol-lowering agents (i.e., cholestyramine, lovastatin). Repeat standardized neurodevelopmental assessments (Peabody and Griffith scales) at 13 and 19 months were normal and magnetic resonance spectra no longer detected the previously observed lipid resonance. Early treatment of Niemann-Pick type C patients with cholesterol-lowering agents appeared to have short-term beneficial effects. Magnetic resonance spectra provided a noninvasive means of monitoring CNS response.

Nerve biopsy findings in Niemann-Pick type II (NPC)

The severe infantile form of Niemann-Pick disease type II was diagnosed in a 4-year-old girl and confirmed by demonstrating in cultured skin fibroblasts a deficiency of low-density lipoprotein-stimulated cholesterol ester synthesis of < 5% of normal. Electrodiagnostic studies revealed changes of a predominantly demyelinating motor and sensory polyneuropathy. Light microscope and ultrastructural examination of a peroneal nerve biopsy showed unique changes. Compacted myelin sheaths were disproportionately thin with marked globular irregularities in single teased nerve fibres and evidence of chronic demyelination. The majority of axons were preserved but axonal spheroids and cytoskeletal abnormalities akin to neuroaxonal dystrophy were noted. Membrane-bound multi-lobulated lysosomal inclusions of floccular and electron-dense material were present in Schwann cells (SC), endoneurial fibroblasts, macrophages, pericytes and endothelial cells. SC of myelinated fibres were stuffed with whorls of concentric osmiophilic membraneous profiles and electron-lucent material. The findings are diagnostic and differ from those of classical Niemann-Pick disease.

Niemann-Pick disease

Results of the investigation carried out during this decade brought unambigous evidence of biochemical heterogeneity inside the complex of Niemann-Pick disease according to which two entirely different metabolic disorders can be recognized. 1. Niemann-Pick sphingomyelinosis, a clear-cut enzymopathy, the pivotal lesion of which is the deficiency of lysosomal spingomyelinase leading to widespread lysosomal deposition of sphingomyelin liquid crystals. Two main allelic variants are known. The first one, neuronopathic (former type A) known as infantile with rapid course, may also manifest considerably prolonged course or an atypical course with predominantly visceral symptomatology. Patients with the second, visceral, variant (former type B), display mainly slow clinical course and often reach adulthood. With rare exceptions the neuronopathic variant can be biochemically recognized from the visceral one by much lower values of the in vivo sphingomyelin degradation test in the former. 2. The rest of the complex comprising types C-D differs substantially from the sphingomyelinase deficiency group by the remarkable heterogeneity in the lysosomal stored lipid pattern given by differences among the affected cell populations. Sphingomyelin storage could be proved histochemically solely in the histiocytic population together with cholesterol, neutral glycosphingolipids and lysobisphosphatidic acid, whereas the brain neurons displayed only neutral glycosphingolipid storage. There is an increasing evidence of the crucial biochemical lesion in this group being an altered intracellular traffic of exogenously derived cholesterol caused probably by its deficient translocation from lysosomes to other intracellular membrane sites. This leads to decreased cholesterol esterification rate which is the basis of the newly developed diagnostic test. Inconstant depression of sphingomyelinase activity is considered to be a secondary phenomenon. The so-called lactosylceramidosis is a rare variant pertinent to this group. The biochemical nature of type E still awaits clarification. Both groups of Niemann-Pick disease display clinical and especially histochemical features which allows to establish diagnosis in a highly efficient way already at the clinicopathological level.

The diverse neurological features of Niemann-Pick disease type C: a report of two cases

Two cases of Niemann-Pick disease type C are described in order to illustrate the variable neurological features of this rare condition. One presented with a predominantly akinetic-rigid syndrome at the age of 5 years. The second developed progressive ataxia, accompanied by a vertical gaze palsy, when she was 13. Neither patient had hepatosplenomegaly; the diagnosis of Niemann-Pick disease type C was based on finding foamy storage cells in bone marrow aspirates.

Lymphocyte autofluorescence: a screening procedure for neurodegenerative diseases

We examined the buffy coats from 12 consecutive patients with neurodegenerative diseases to determine the value of autofluorescence study by fluorescence microscopy in parallel with electron microscopy, as a rapid and inexpensive screening procedure for lymphocyte inclusions characteristic of neuronal ceroidlipofuscinoses. Four patients (3 with neuronal ceroidlipofuscinoses and 1 with Hallervorden-Spatz syndrome) had discrete, yellow-orange, 1-2 microns autofluorescent granules in the cytoplasm of some lymphocytes. These granules corresponded to characteristic inclusions of neuronal ceroidlipofuscinoses demonstrated by electron microscopy. Five patients (4 undiagnosed or nonspecific disease, and 1 with Leber congenital amaurosis) had hazy green cytoplasmic autofluorescence which correlated with parallel tubular arrays in lymphocytes. The 3 patients with no autofluorescence had no ultrastructural lymphocytic inclusions. We conclude that buffy coat autofluorescence is a rapid and inexpensive method of identifying specimens that require electron microscopic confirmation, and the absence of autofluorescence of lymphocytes in a buffy coat specimen eliminates the necessity for electron microscopic examination. However, characteristic ultrastructural inclusions associated with neurodegenerative diseases may occur in other tissues, such as skin and conjunctiva.

Pelizaeus-Merzbacher disease. The Löwenberg-Hill type

The clinical and neuropathological findings are reported of two sibs with adult type PMD. Clinical features deviating from the usual pattern included: no psychosis, no measurable dementia, no dwarfism, no microcephaly, no (marked) involuntary movements, but conspicuous generalised muscle atrophy and denervation, impairment of vital and gnostic sensation, thoracolumbar vertebral anomalies, and aplasia of os coccygis. Neuropathological findings were as usual, with additional unusual features: pinhead-size areas of acute myelin-abbau products, involvement of grey in addition to white matter, and upon ultrastructure, the new finding of intra-oligodendroglial fingerprint bodies, both in neuronal satellite and in white matter oligoglia, but not in astrocytes, ganglion cells, or pericytes. This excludes the origin of the stored material in the lysosomes as to derive exclusively from demyelination and would possibly imply PMD to be an oligodendroglial lysosomal storage disease.

Hemidystonia: a report of 22 patients and a review of the literature

Hemidystonia defined as involuntary, sustained posturing of the unilateral arm, leg, and face was studied in 12 male and 10 female patients. Hemidystonia was caused by cerebrovascular disease in eight patients, perinatal trauma or childhood injury in four, head trauma and its sequelae in three, neuronal storage disorders in two, neurodegenerative disease in two, lesions after thalamotomy in two, and presumed encephalitis in one. Sixteen patients (73%) had CT evidence of contralateral basal ganglia damage, history of hemiparesis, or both. Brain damage before 7 years of age produced contralateral hemidystonia with a mean delay of 9-7 years. In older patients hemidystonia appeared within 6 months after injury. Hemidystonia may result from a disconnection between the striatum and the thalamus with relative preservation of the corticospinal pathways.

A progressive neurologic disorder with supranuclear vertical gaze paresis and distinctive bone marrow cells

Nine patients with a progressive neurologic disorder that was characterized by mental deterioration, supranuclear vertical gaze paresis, and foam cells or sea-blue histiocytes in the bone marrow are described and compared with patients who were previously described as having " neurovisceral storage disease with vertical supranuclear ophthalmoplegia" and "dystonic lipidosis." The clinical manifestations of our patients and those described by others and the pathologic findings and profiles of lipid analysis reported by others are similar to those in patients with Niemann-Pick disease, type C. Sphingomyelinase activities in leukocytes and skin fibroblasts were normal in our patients and in more than half of the reported cases; these findings are also compatible with those in patients with Niemann-Pick disease, type C. Until the biochemical and genetic abnormalities of Niemann-Pick disease, type C are clearly defined, it is justifiable to classify the disorder under discussion as a subgroup of Niemann-Pick disease, type C because it seems to be a heterogeneous group. From the clinical point of view, the diagnosis is difficult to establish in the absence of abnormalities in the bone marrow in patients who are older than 20 years; repeat examinations of the bone marrow are necessary in such patients. Clinicians should be aware of this disorder not only in patients in the first and second decades of life, when this disorder usually becomes symptomatic, but also in patients in the fourth and fifth decades.

Studies on sphingomyelinase and beta-glucosidase activities in Niemann-Pick disease variants. Phosphodiesterase activities measured with natural and artificial substrates

Cultured fibroblasts were studied from 12 cases of Niemann-Pick disease group C. In 11, sphingomyelinase and glucocerebrosidase (and beta-glucosidase) activities were reduced to around 50% of those of controls. On isoelectric focusing, all 12 strains lacked sphingomyelinase activity in the major cathodic region (pI 8.0). The defect was also demonstrated with the artificial phosphodiester substrates bis(4-methylumbelliferyl) phosphate and 4-methylumbelliferyl pyrophosphate diester. In control fibroblasts and those heterozygous for types A or B or group C Niemann-Pick disease, the major sphingomyelinase peak electrofocused at pI 8.0. No direct interaction could be demonstrated by mixing experiments between group C Niemann-Pick extracts and those of type A disease or Gaucher disease. Profiles for beta-glucosidase activity appeared normal in Niemann-Pick group C fibroblasts. No reduction of sphingomyelinase or glucocerebrosidase activities was found in Niemann-Pick group C liver, nor any attenuation of cathodic sphingomyelinase activity in the affected tissue. Results suggest that sphingomyelinase expression differs in fibroblasts and liver. Enzyme defects associated with Niemann-Pick disease group C were only observed in cultured cells.

Biochemical studies in Niemann-Pick disease. I. Major sphingolipids of liver and spleen

In liver and spleen specimens of 12 patients with Niemann-Pick disease types A or B, sphingomyelin was increased 15-45-fold, total phospholipids 4-10-fold and cholesterol 3-6-fold over the normal values. The storage pattern was qualitatively similar in both types but the degree of accumulation was less in type B. In Niemann-Pick disease type C (16 cases), sphingomyelin was increased 3.5-fold in liver and 6-fold in spleen. In all forms of Niemann-Pick disease, bis(monoacylglycero)phosphate was markedly elevated. Glycosphingolipids were studied in six cases with type C, three cases with type B and two cases with type A. Glucosylceramide showed the largest increase from the normal pattern in all types of Niemann-Pick disease. Highest values were recorded in type C, 14- and 35-fold normal concentrations in liver and spleen, respectively. Other neutral glycosphingolipids, particularly lactosylceramide, were also elevated, and a 2-4-fold increase of ganglioside GM3 occurred. The fatty acid profiles of the sphingolipids showed only minor alterations. In contrast to the largely dominating sphingomyelin storage found in liver and spleen of Niemann-Pick disease types A and B, the major characteristic of the lipid storage in Niemann-Pick disease type C was the absence of any prevailing accumulation and, thus, the concept of this disorder as a primary sphingomyelin storage disease is not founded.

Adult neurovisceral lipidosis compatible with Niemann-Pick disease type C

The authors present a case of neurovisceral storage disease with the whole of its clinical course confined to adult life (symptoms from 26 to 46 years of age) and marked by mainly neurological symptomatology with dystonia, vertical supranuclear ophthalmoplegia and progressive mental deterioration as the dominant features. From the results of postmortem structural histochemical and chemical analysis the case was diagnosed as Niemann-Pick disease type C. This case, together with sporadic observations reported by other authors, represents a significant shift in our view of the incidence of NPD type C in older age groups.

Chemical and biochemical studies in fetuses affected with Nieman-Pick disease type A

Chemical and biochemical studies were performed on two unrelated fetuses affected with Niemann-Pick disease type A, following abortion at about the 19th week of gestation. Abortion was performed as a consequence of previous findings, in amniotic fluid cell cultures, that sphingomyelinase activity was completely absent. Phospholipid analyses of various organs of the fetuses, spleen and liver were the organs mostly affected. Interestingly enough considerable accumulation of sphingomyelin was found in the placenta. The brain was the only organ in which sphingomyelin storage could not be proved. In addition to sphingomyelin a slight accumulation of cholesterol was noticed. Deficiency of sphingomyelinase activity measured at pH 5.0 was the general characteristic of the affected tissues. It is concluded that the accumulation of sphingomyelin in various organs throughout the body of fetuses affected with Niemann-Pick disease is suggestive of the essential role of the enzyme sphingomyelinase and its biochemical maturation, even during the early stages of gestation.

Retinal abnormalities in ophthalmoplegic lipidosis

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An ultramicroscopic study of skin and conjunctival biopsies in chronic neurological disorders of childhood

One hundred twenty-seven skin and 59 conjunctival biopsies were performed in 136 pediatric patients with chronic neurological disorders. Ultrastructural abnormalities were found in 48 of 72 patients with unequivocally progressive encephalopathies (67 of which could not be diagnosed by biochemical means) and in 4 patients with miscellaneous disease (fetal rubella syndrome and hereditary motor-sensory neuropathy), but in none of 55 patients with static or dubiously progressive encephalopathies. Of the 48 positive biopsies in the group with progressive encephalopathies, 39 showed abnormalities characteristic enough to permit a specific diagnosis (lysosomal storage disorders, neuroaxonal dystrophy, ophthalmoplegia-plus) in conjunction with a compatible clinical picture. In 9 cases no diagnosis could be made despite the finding of lamellar or vacuolar inclusions. In no case were discrepancies observed between the results of skin and conjunctival biopsies. Although biochemical analysis is the simplest and most effective technique for the diagnosis of most progressive encephalopathies, skin or conjunctival biopsy is a valuable procedure in patients without detectable enzyme deficiency.

Morphological diagnosis of Niemann-Pick disease type C by skin and conjunctival biopsies

Skin and conjunctival biopsies were performed in six children with mental deterioration, incoordination, involuntary movements and discrete visceromegaly. Two main types of inclusions were observed: 1) intracytoplasmic bodies containing membranous profiles loosely disposed in concentric or parallel arrays, lying in clear cells of eccrine sweat glands, hair follicles and cells of the basal layer of skin and 2) pleomorphous membrane bound bodies with a multivesicular aspect which are formed by vacuoles, stacks of lamellae and amorphous electron dense material. Subsequent biochemical studies showing a slight increase of sphingomyelin in liver and normal sphingomyelinase in leukocytes supported the morphological diagnosis of Niemann-Pick disease type C. The qualitative regional diversity of storage is stressed and the interest of both skin and conjunctival biopsies in the diagnosis of this affection is discussed.

Somatic cell hybridisation studies showing different gene mutations in Niemann-Pick variants

Cultured skin fibroblasts from patients with different clinical types of Niemann-Pick disease were hybridized and sphingomyelinase activities were measured in the heterokaryon cell population. Both the natural substrate (3H-choline) sphingomyelin and the chromogenic analogue hexadecanoylamino-4-nitrophenylphosphorylcholine were used in the complementation analysis. In fusions between cells from type C Niemann-Pick disease with those from type A or B a clear restoration of sphingomyelinase activity occurred, whereas no complementation was found in other fusion combinations. The results indicate that at least two different genes are involved in the mutations leading to the different Niemann-Pick variants.

Chemical and biochemical studies in human fetuses affected with Niemann-Pick disease type A

Chemical and biochemical studies were performed on two unrelated fetuses affected with Niemann-Pick disease type A, following abortion at about the 19th week of gestation. Abortion was performed as a consequence of previous findings, in amniotic fluid cell cultures, that sphingomyelinase activity was completely absent. Phospholipid analyses of various organs of the fetuses revealed an excess of sphingomyelin in all viscera as compared to control nonaffected fetuses. Spleen and liver were the organs mostly affected. Interestingly enough considerable accumulation of sphingomyelin was found in the placenta. The brain was the only organ in which sphingomyelin storage could not be proved. In addition to sphingomyelin a slight accumulation of cholesterol was noticed. Deficiency of sphingomyelinase activity measured at pH 5.0 was the general characteristics of the affected tissues. It could be concluded that the accumulation of sphingomyelin in various organs throughout the body of fetuses affected with Niemann-Pick disease, was suggestive of the essential role of the enzyme sphingomyelinase and its biochemical maturation, even during the early stages of gestation.

Diagnosis of Niemann-Pick disease using a simple and sensitive fluorimetric assay of sphingomyelinase activity

Phosphodiesterase activity of cultured cells was determined with bis-(4-methylumbelliferyl) phosphate as substrate. In the presence of Triton X-100 an acid component was evident and results indicated that this enzyme was identical with sphingomyelinase. Acid phosphodiesterase activity was specifically inhibited by sphingomyelin. In fibroblasts from patients with Niemann-Pick diseases types A, B and C, acid phosphodiesterase activity was deficient whereas neutral activity was normal. Neutral activity could, however, be removed by acid precipitation or by binding to DEAE-cellulose. Hence a simple and sensitive fluorimetric method is described for the assay of sphingomyelinase activity in the diagnosis of Niemann-Pick disease.

Paired helical filaments in neurovisceral lipidosis (juvenile dystonic lipidosis)

Paired helical filaments, the ultrastructural substrate of Alzheimer neurofibrillary change, were found in great number in a 29-year-old patient with neurovisceral lipidosis. The abnormal filaments were frequently present in the distended neurons and axons. The clinical, pathological, and ultrastructural findings were consistent with juvenile dystonic lipidosis, which is considered to be a variant of type C Niemann-Pick disease. The association of Alzheimer neurofibrillary change and central nervous system lipidosis is reviewed.

An unusual case of phospholipidosis

We present the results of a structural, histochemical and lipid-chromatographic study of tissues obtained at postmortem from an unusual case of phospholipidosis. A previous biopsy of the appendix and liver (Elleder et al., 1975a) had revealed a predominance of phosphoglyceride storage, principally of lysobisphosphatidic acid (LBPA) postmortem material showed that this lipid was stored exclusively in central neurons. In the spleen and the lymph node, however, sphingomyelin (SP) was shown, histochemically and chromatographically, to be the main lipid stored. Total sphingomyelinase (SPase) activity in the appendix was reduced to about 50% of normal. Neuroaxonal dystrophy (NAD) and a conspicuous discrepancy between the degree of distension of some neurons and their lipid content deserve special mention. The case is contrasted with classical sphingomyelinosis; the complexity of the Niemann-Pick group of diseases is discussed as an indication of the difficulties of classification of any atypical case.